/*

 * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import java.io.BufferedReader;

import java.io.ByteArrayInputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.util.ArrayList;

import java.util.List;

/**

 * HexDumpReader provides utility methods to read a hex dump text file

 * and convert to an InputStream.  The format supported by the methods

 * can be generated by the following command.

 *

 * $ od -vw -t x1 foo | sed -r -e 's/^[0-9]+ ?//' -e 's/ //g' -e '/^$/d'

 */

public class HexDumpReader {

    public static InputStream getStreamFromHexDump(String fileName) {

        return getStreamFromHexDump(new File(System.getProperty("test.src", "."),

                                             fileName));

    }

    public static InputStream getStreamFromHexDump(File hexFile) {

        ByteArrayBuilder bab = new ByteArrayBuilder();

        int lineNo = 0;

        try (BufferedReader reader

                 = new BufferedReader(new InputStreamReader(new FileInputStream(hexFile),

                                                            "us-ascii"))) {

            String line;

            while ((line = reader.readLine()) != null) {

                lineNo++;

                line = line.trim();

                // Skip blank and comment lines.

                if (line.length() == 0) {

                    continue;

                }

                int x = line.indexOf('#');

                if (x == 0) {

                    continue;

                }

                if (x > 0) {

                    line = line.substring(0, x).trim();

                }

                int len = line.length();

                for (int i = 0; i < len; i += 2) {

                    bab.put((byte)Integer.parseInt(line, i, i + 2, 16));

                }

            }

        } catch (Exception e) {

            throw new RuntimeException(hexFile.getName() + ":error:" + lineNo + ": " + e, e);

        }

        return new ByteArrayInputStream(bab.toArray());

    }

    private static class ByteArrayBuilder {

        private static final int BUFFER_SIZE = 4096;

        private int size;

        private List<byte[]> bytes;

        private byte[] current;

        private int offset;

        ByteArrayBuilder() {

            bytes = new ArrayList<>();

            current = new byte[BUFFER_SIZE];

        }

        void put(byte b) {

            if (offset == BUFFER_SIZE) {

                bytes.add(current);

                current = new byte[BUFFER_SIZE];

                offset = 0;

            }

            current[offset++] = b;

            size++;

        }

        byte[] toArray() {

            byte[] buf = new byte[size];

            int ptr = 0;

            for (byte[] ba : bytes) {

                System.arraycopy(ba, 0, buf, ptr, ba.length);

                ptr += ba.length;

            }

            System.arraycopy(current, 0, buf, ptr, offset);

            assert ptr + offset == size;

            return buf;

        }

    }

}